UPDATE 1-Thai AIS plans to sell Apple's iPhone 4
* AIS to be third operator selling iPhone in Thai market
* Smartphone is key growth driver for mobile data
* TAC to invest 1 bln baht to upgrade data network
* AIS shares up 1.8 pct, outperform the market (Adds details)
BANGKOK, Sept 9 (Reuters) - Thailand's top mobile phone operator, Advanced Info Service Pcl (AIS) ADVA.BK, said on Thursday it would sell Apple Inc's (AAPL.O) iPhone 4 in Thailand in coming months, a move that should boost its revenue from data services.
AIS, 21 percent owned by Singapore Telecommunications Ltd (STEL.SI), would become the third operator to sell the iPhone in the Thai market after True Move, a subsidiary of True Corp Pcl (TRUE.BK), and Total Access Communication Pcl (DTAC.BK) (TACC.SI).
AIS gave no details in its statement.
The iPhone, Apple's main growth driver, is expected to help drive revenue for mobile operators in Thailand, where data services have shown stronger growth than voice services in a saturated market where almost everyone has a mobile phone.
Data growth is likely to accelerate with the arrival of 3G services, expected in the second half of next year following auctions for 3G licences starting this month.
Mobile operators in Thailand are banking on the success of smartphones such as Apple's iPhone and Research In Motion's RIM.TO RIMM.O BlackBerry.
Thailand has more than 5 million smartphones, of which 800,000 are high-end phones.
In May, AIS announced plans to join forces with a Thai unit of Samsung Electronics Co Ltd (005930.KS) to launch Android-based Galaxy S smartphones.
Thailand's telecoms industry is expected to grow 5 percent this year due to a pick-up in economic growth, and data revenue is expected to rise 25-30 percent, AIS has said.
TAC, controlled by Norway's Telenor, said in a separate statement it planned to invest more than 1 billion baht ($32 million) to upgrade its data network in response to strong growth in data services, boosted by the popularity of smartphones, social networks and multimedia applications.
At 0840 GMT, AIS shares were up 1.8 percent at 99.25 baht, after hitting a two-year high of 100.50 baht. The broader thai market .SETI was 0.1 percent lower. ($1 = 30.86 Baht) (Reporting by Khettiya Jittapong; Editing by Alan Raybould)